1. Field of the Invention
The present invention relates to a substrate transporting apparatus that transports a substrate, a substrate platform shelf where the substrate is placed and a substrate processing apparatus that processes the substrate.
2. Description of the Background Art
Substrate processing apparatuses have been conventionally used to perform various types of processes on substrates such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks or the like.
The substrate processing apparatus described in JP 10-150090 A is explained as an example of the substrate processing apparatus. FIG. 11 is a plan view showing the substrate processing apparatus described in JP 10-150090 A. As shown in FIG. 11, this substrate processing apparatus 900 includes an indexer 910 and a processing module 920.
The indexer 910 includes an indexer robot 912 that moves back and forth along an indexer transport path 911 that linearly extends and a cassette platform 913 where a plurality of carriers C can be placed along the indexer transport path 911. The plurality of substrates W are stored in the carriers C.
The processing module 920 includes a main transport robot 922 that moves back and forth along a main transport path 921 that is perpendicular to the indexer transport path 911 and a pair of unit sections 930A, 930B provided such that the main transport path 921 is sandwiched therebetween. Processing chambers 933, 934 for performing processing on the substrate W are provided in each of the unit sections 930A, 930B. In the substrate processing apparatus 900, transportation of the substrate W is performed as follows.
First, the carrier C is carried into the cassette platform 913 from outside of the substrate processing apparatus 900. Then, the unprocessed substrate W stored in the carrier C is taken out by the indexer robot 912 and transferred to the main transport robot 922.
The substrate W transferred to the main transport robot 922 is carried into the processing chambers 933, 934 and subjected to cleaning processing. Thereafter, the processed substrate W is again stored in the carrier C by the main transport robot 922 and the indexer robot 912.
In the above-described substrate processing apparatus 900, the indexer robot 912 includes a substrate taking out arm for taking the unprocessed substrate W out of the carrier C and a substrate storing arm for storing the processed substrate W in the carrier C.
For example, the indexer robot 912 takes the unprocessed substrate W out of the carrier C and transports it, and transfers the substrate W to the main transport robot 922. Also, the indexer robot 912 receives the processed substrate W from the main transport robot 922 and transports it, and stores the substrate W in the carrier C.
In the operation of the indexer robot 912, the carrier C of which the indexer robot 912 takes the unprocessed substrate W out and the carrier C in which the indexer robot 912 stores the processed substrate W are different from each other in some cases.
In this case, after storing the processed substrate Win one carrier C, the indexer robot 912 must move along the indexer transport path 911 toward the other carrier C in which the unprocessed substrate W is stored. This prevents the throughput in the substrate processing apparatus 900 from being improved.
Therefore, it is proposed that the operation speed of the indexer robot 912 is increased to improve the throughput in the substrate processing apparatus 900. However, the operation speed of the indexer robot 912 can not be remarkably increased due to the following reasons.
In the carriers C, the spacing for storing the substrates W is very small in order to store more of the substrate W. Thus, the substrate taking out arm and the substrate storing arm of the indexer robot 912 are manufactured so that their radial thicknesses are small, corresponding to the spacing for storing the substrate Win the carriers C. Therefore, rigidity of the substrate taking out arm and the substrate storing arm is not very high.
Accordingly, if the operation speed of the indexer robot 912 is remarkably increased, vibration, deformation or the like is generated to each of the arms. This causes poor transportation of the substrate W.